1. Field of the Invention
The present invention generally relates to the field of filtration systems. More specifically, embodiments of the present invention pertain to improved filtration systems for removing particulate matter from cooling tower basins.
2. Background and Description of Related Art
Some conventional cooling tower systems include (i) a sweeper located on the floor of the basin to assist in the buildup and removal of particulate matter and (ii) a centrifugal separator for separating particulate-laden fluid from the basin into fluid and particulate matter components. In some conventional systems, the filtering system is closed loop—namely, the fluid that has been separated from the particulate matter by the centrifugal separator may be recycled back into the sweeper.
Conventional sweeper assemblies may include a plurality of amplifying water jet sprayers, or eductors. The eductors may receive fluid from the fluid output of the centrifugal separator and direct said output towards a suction intake, effectively sweeping particulate matter across the basin floor. The eductors amplify the amount of fluid discharged from the nozzle—typically by a factor of 5—by drawing in fluid from the surrounding area in the basin along with fluid supplied via the fluid output of the centrifugal separator. In some conventional sweeper assemblies, the eductors are located around a peripheral edge of the basin floor and are directed towards the suction intake such the particulate-laden fluid can be removed therefrom.
Conventional centrifugal separators (such as that disclosed in U.S. Pat. No. 7,335,313, incorporated herein by reference) utilize centrifugal force and gravity to achieve varying degrees of separation of particulate from particulate/fluid mixtures. The separated particulates generally settle to the bottom of the centrifugal separator in a sediment chamber from which they are periodically removed. Some conventional separators employ a vortex system where the particulate/fluid mixture is introduced into a cylindrical chamber at a tangential angle generating centrifugal action in the mixture. Some conventional separators include a spin plate at the bottom of a vortex tube that reverses the axial direction of flow. The separated fluid exits through a smaller tube provided at the top of the cylindrical chamber, while the solids settle below the spin plate in the sediment chamber.
Unfortunately, it has been determined that the use of eductors introduces turbulence in the basin which decreases the cleaning effectiveness. The trend in conventional approaches is to increase the number or eductors and/or the output volume or pressure requirements, both of which increase the cleaning system power requirements. It is to be appreciated that conventional use of eductors requires significant system pressure which in turn significantly increases operational costs. For example, in order to achieve a 5:1 amplification power, the eductors require system pressure of about 20 psig.
It has also been determined that conventional vortex-based centrifugal separators introduce turbulence within the separator body, also decreasing the cleaning effectiveness. It is believed that appreciable turbulence is introduced by (i) the introduction of the particulate/fluid mixture, (ii) vibratory action at specific flow velocities, and (iii) the accumulation of air in the dead zone above the inlet. This increased turbulence increases the horsepower requirement for the suction pump, also increasing the total cleaning system power requirements.
It is therefore desirable to provide sweepers, separators, and cleaning systems having reduced fluid turbulence.